Acute aortic dissection (AAD) is associated with an inflammatory reaction, as evidenced by elevated inflammatory markers, including C-reactive protein (CRP). The association between the peak CRP level and long-term outcomes in type B AAD has not been systematically investigated. The purpose of this study was to investigate whether the peak CRP level during admission predicts long-term outcomes in type B AAD. We conducted a clinical follow-up study of type B AAD. We divided the study population into 4 groups according to the tertiles of peak CRP levels (T1: 0.60 to 9.37 mg/dL; T2: 9.61 to 14.87 mg/dL; T3: 14.90 to 32.60 mg/dL; and unavailable peak CRP group). Multivariate Cox regression analysis was applied to investigate whether the tertiles of peak CRP predict adverse events even after adjusting for other variables. A total of 232 type B AAD patients were included in this analysis. The median follow-up period was 50 months. CRP reached its peak on day 4.5+/-1.7. Mean peak CRP values in T1, T2, and T3 were 6.4+/-2.4, 12.0+/-1.5, and 19.5+/-4.0 mg/dL, respectively. There were 65 events (39 deaths and 26 aortic events) during the follow-up. T3 and T2 (versus T1) were strong predictors of adverse events (T3: hazard ratio: 6.02 [95% CI: 2.44 to 14.87], P=0.0001; T2: hazard ratio: 3.25 [95% CI: 1.37 to 7.71], P=0.01) after controlling for all of the confounding factors. In conclusion, peak CRP is a strong predictor for adverse long-term events in patients with type B AAD.